In this article I will focuse on installed Linux (fedora distribution -29 server edition) like a guest into VirtualBox and like a host OS will be Windows OS.
Before we can use sharing folders between both systems, we have to download from this https://www.virtualbox.org/wiki/Downloads.

We need to download VirtualBox in our case for Windows hosts version and extension pack and install it. After installation both files we can see in VirtualBox menu File/Preferences/Extensions extension pack.

After instalation fedora OS into VirtualBox we can login as root and do folowing

• go to the VirtualBox menu/devices/Insert guest additions CD Image…
• run these comands

# dnf update kernel*
# dnf install make gcc  dkms bzip2 perl kernel-headers kernel-devel
# sudo mount -r /dev/cdrom /media

# cd /media
# sudo ./VBoxLinuxAdditions.run 

• restart linux with command reboot
• login as root and use these commands

# mkdir /usr/share/myshare

• set on your host OS your share folder in VirtualBox

• and go back in to you quest Os Linux (fedora) and mount your Window folder into Linux OS with this command

# mount -t vboxsf fedora_share /usr/share/myshare

According to user who will use this share we need to set permission

# sudo adduser username vboxsf

• if you want to have share folder available upon start from guest (Linux – Fedora) folow this steps

# nano /etc/fstab

add folowing line at the end

fedora_share    /usr/share/myshare    vboxsf  comment=systemd.automount     0       0